Blue Smoke = Oil Leak

[xdelirious45x]

:headwall I recently purchased a 1988 Chevrolet V10 Full Size Blazer 4x4. It has a 5.7L 350c.i.d. TBI engine. I am restoring it from the inside out. I recently welded the holes in the chassis, put a new starter, distributor, distributor cap & rotor, spark plug wires, spark plugs, changed oil, trans flush, installed new carpet, radio, replace tailgate window regulator, and did many other things. However, I ran into a problem when I noticed there is blue smoke that blows from the exhaust whenever i hit the gas. I do not have an extensive knowledge with crankshafts, pistons, valves, or any of that sort. I know it is an oil leak however, I do not know the exact location. I have heard places such as blown head gaskets, bad valve guides, burnt piston rings, which can all cause oil to leak into the head. Any ideas or comments would be helpful????

Thank You.

:headwall

[wyldman]

It could be several things.

A vacuum leak at the intake,into the crankcase would suck oil into the cylinders.You would notice poor running,and most likey a miss associated with it.A bad PCV could also be sucking oil.

Sticky,broken or worn rings.A ring problem will give you smoke all the time.If the vehicle was not properly maintanied,then the rings could just be gummed up and sticking.

Bad valve guides,and\or stem seals.This will normally give you a pretty good puff of smoke on startup,and small puffs on deceleration.If the smoke is real bad,the vavle guides may be worn,and it will require removing the heads.

I'd start by flushing\changing the oil,and make sure it's not overfull.Drive it for a bit and see if it gets any better.A few quick oil changes may help clean things up some.I would also replace the PCV,just to make sure.

If it doesn't get any better,next step would be to do a compression test\leakdown check to see what shape the motor is in.

[xdelirious45x]

Yes, I changed the PCV and the elbow. When the truck starts it does puff out a good amount of the smoke. I did the oil change using Quaker State higher mileage oil and Lucas oil stabilizer. I am not sure how the truck was maintained because I purchased it from a used car lot. It was a good buy for the price. I noticed you are an ASE Master Tech, and I work at a Volvo Dealership in New Jersey, therefore I will be able to ask one of our tech's to see if they can find a leak or do a compression test to find a leak somewhere.

Would taking out the heads be a difficult job to do? What is really involved, taking out cams, gaskets, valves, etc??

I appreciate your response! Thank you

[wyldman]

The heads aren't too hard.No cams or gears to touch,just gotta pull the distributor.As long as you mark it,and don't turn the engine you will be fine.

If it's puffing a good amount of smoke when you start it,then it's probably valve stem seals.The valve guides may be getting loose too.I'd just throw a set of valve stem seals in in first,as they are dirt cheap (a few bucks),and not hard to do.

All you need is a compression tester adaptor and a compressed air source.Pull the rocker covers,and using a special tool (like a big prybar),take off the valve springs and replace the seals.The compressed air is used to keep the valve closed,and prevent it from falling into the cylinder.

Even if the guides are bad,the new seals will help make it a little better.You can also switch to a positive retention seal which pushes down onto the valve guide boss,and does a much better job of controlling oil.

[Z71]

More than likely a worn out engine. Anything that smokes as bad as this ahs got to be on its way out.

Btw-The 350 is a not a V10.

[xdelirious45x]

I do not believe it is a worn out engine. Everything runs great, and i can see the previous owner kept everything stock. I appreciate all the help from you guys. And if there are any other's with any ideas or comments i would appreciate hearing them.


BTW: IT IS A CHEVROLET V10 BLAZER
with a 8 cyl. 5.7L 350c.i.d. TBI

For future reference, so you dont look foolish,

V10 is NOT the engine model.
It is the Truck Model.

Similar to a Chevrolet S10 Blazer
With a 6 cyl engine.

Thank you anyway!

[wyldman]

GM changed the old body style designation to the V\R series,when the new body style took over the C\K series designation.

The older body style was used on Jimmy\Blazers and Suburban,and some 1 ton and crew cab models until 1991.

I don't think the engineis worn out either,or there would be other symptoms.See if one of the mechanics can throw the valve stem seals in for you on the side.Shouldn't take more than an hour or two.

[Z71]

If its coming out of the tail pipe, its an internal engine problem. It still could run great and the oil rings are shot. Rings are shot.

[towman]

gee i guess i better go outside and tell my truck the engine is shot in it, i to had oil smoke out of the tail pipe and a good set of valve stem seals cleared it right up, very typical for a small block chevy

[Z71]

Typical? I have owned dozens of GM cars and truck dating back to 1963 and never had one smoke or ever know of anyone with valve seal problems. Not saying you are not correct but its not as common from my perspective. If the vehicle was not properly serviced or it was well used then these things can occur but typical?

I just called a Friend who has been a master mechanic since 1966 and he said the tell-tale sign of bad valve guide seals its a big cloud of smoke on start up in AM, or smoking a lot coasting, like downhill etc. For it to smoke heavily on acceleration the seals would have to be totally gone. Engines are hopped up, a good many times the heads will have valve seal problems that can be traced to improper or poor quality parts, over doing the performance parts or unskilled work.

This is just an opinion and you may be correct, it is the valve guide seals but there is a high probability its something much worse.

[Z71]

Originally posted by xdelirious45x
I do not believe it is a worn out engine. Everything runs great, andBTW: IT IS A CHEVROLET V10 BLAZER
with a 8 cyl. 5.7L 350c.i.d. TBI

For future reference, so you dont look foolish,

V10 is NOT the engine model.
It is the Truck Model.

Similar to a Chevrolet S10 Blazer
With a 6 cyl engine.

Thank you anyway!

I new that already having owned one, a 1987 Chevrolet Silverado C1500.

[wyldman]

Valve stem seals are VERY common problems on a small block Chevy,and have been for a long time.

They are just a little rubber "O" ring,which gets brittle and shrinks over time.Changing them is easy,and they cost very little.For what it's worth,he's got nothing to lose trying a set to see if it helps with the problem.

If the seals are totally gone,then it will smoke all the time,sometimes worse on accel,as the oil trickles down the valve stem when you idling,and then gets burnt off (producing the smoke) when you get on it.

[John DiMartino]

I replaced the valve seals in my 89 GMC's 350 TBI ,it stopped 99% of the smoke at idle,and start up. Valve guides/seals were such a big problem on small blocks there are even a few TSBs pertaining to them,esp in the 350TBIs built at the flint engine plant in the late 80's/. My 89 was a flint engine,and was affected,but never brought in,I had to replace them out of warranty.

Z71, if you knew the V10 was the model like you claim why did you say this: Btw-The 350 is a not a V10. You just contradicted yourself.

[Z71]

I was making a joke but I guess you guys are in a bad mood.

[Z71]

vehicle I have owner and never had a smoking problem

In order of ownership

1966 Impala SS396 (New)
1970 Chevelle SS454 (New)
1972 El Camino SS350 (new)
1973 Chevelle SS350 (new)
1966 GTO (used)
1975 GMC Sierra Grande 4x4 (used)
1977 Monte Carlo (new)
1979 3/4 ton custom Chevy Van (new)
1982 S10 Tahoe Pickup 9new)
1981 Olds Cutlass Supreme (used)
1984 Olds Delta 88 (new)
1987 Chevrolet Silverado 2x4 R10 (new)
1988 Chevrolet Silverado 2x4 (new)
1964 Impala 2 dr sport coupe (basket case and restored it)
1989 Chevrolet Silverado 4x4 Z71 (new)
1990 Lumina Euro (new)
1992 Chevrolet Silverado 4x4 E. Cab Z71 (new)
1970 El Camino SS396 (used)
1994 Lumina Z34 (new)
1995 Blazer LT 4x4 (new)
1996 Chevrolet Silverado E. cab Z71 (new)
1998 Monte Carlo Z34 (new)
1999 GMC Sierra SLE E. Cab Z71 (new)
2001 GMC Sierra SLT E. Cab Z71 (new)
2002 Pontiac Trans Am WS6 (new)
1992 Chevrolet Silverado SWB 4x4 plow truck (used 03)

Did I really have all these? I think I missed a few. Had to have 2 vehicles because I traveled 25,000 miles+ a year for work and had to have something at home for the family to use.:)
http://www.synthetic-oil.com/images/92plow.jpg
http://www.synthetic-oil.com/images/US41.JPG

[ratlover]

the sbc's and the 4.3's that use the goofy o ring type valve seals are known for this problem. pretty common knowledge. it starts as a puff on start up and can turn to something that looks like a misquito fogger after they really go. Seems that a car dealer will dump some smoke be gone in there when some one buys it and after they change the oil it seems to just appear.

Seals are just a kinda quick fix and very easy to do and the seals are cheap(mostly cuz they sell so many of em). You can buy one of those air adapters and a good spring compressor(I've used those goofy pry bar looking ones and cursed em, tavia and others makes a good unit that screws onto the stud and copresses the spring easily and gives you plenty of room to deal with the keepers, plus it dosnt take heman to squash a set of double springs+dampner) http://www.tavia.com/cat15.html#2 And you need a good way to turn over the motor, I like the flywheel wrench I have from snapon but you can get a cheapy that works fin too.

[xdelirious45x]

:headwall WHEN THE TRUCK IS IDLING THERE IS NO SMOKE AT ALL, IT RUNS NORMAL, WHEN THE TRUCK STARTS UP IT PUFFS OUT A DECENT AMOUNT OF SMOKE THEN IT GOES AWAY, AND ONLY WHEN I PUSH THE GAS, THE BLUE SMOKE COMES BACK.

Z71 I'M NOT TRYING TO BE MEAN OR ANYTHING I JUST WANT SOME HELP

ALSO, THE TRUCK IS A 4 SPD, WELL L,1,2,3....I WANTED TO KNOW COULD I USE REGULAR 80W-90 GEAR OIL FOR A TRANS FLUSH?:burnout

[scfall]

My 91 was doing the same. I figured it was the valve seals so I replaced them last week and found the pass. side oil return ports plugged up, cleaned them and changed the seals and the problem went away. GOOD LUCK Scott:burnout

[towman]

one last note about valve stem seals, the factory ones are nothing more than little o rings, they do make an umbrella style wich is much better at oil control and will last a lot longer

[xdelirious45x]

Where would I be able to purchase the Vavle Seals & Other Engine Components?
Are there any websites??

[joestewman]

Try Advance Auto or Auto Zone. Probably have them on stock since it is such a small item. My 1983 Chevy Scottsdale smokes a tiny bit. I still hold it wide open and it gets the job done. Especially when your an 18 year old man that has a sweet Magnaflow exhaust. :burnout